Apogee: “Rocket Lab has revealed their larger next generation rocket, a rocket for 2050. In this video I analyze the design decisions for Neutron.”

https://www.youtube.com/watch?v=iqmcm_fblZw

I do not find Neutron and Starship to be an “apples to apples” comparison. Neutron and Falcon 9 are more alike. Different class of launch vehicle. Starship and SLS are closer in class.

Angry Astronaut just posted a vid discussing this. Beck did the research of what people customers need to launch, and found 8 Tons (metric) to be the sweet spot.

I hear a lot of quotes for launch prices. I have never seen the price for a second stage.

I refer to total Neutron rocket system. Only the first stage of the Neutron rocket (including the payload fairing) is to be reused. The second stage of the neutron rocket is not reused and – in contrast to the Starship system – has to be new on every mission. I assume that this is the reason why the second stage of the neutron rocket appears relatively small in relation to the first rocket and Beck has given the first stage more proportion of the total propulsion capacity of the rocket, which should be, however, less favorable for the return flight of the stage and its thermal burden.

Comment: I still know from previous studies on the optimization of launch vehicle systems that the ratio of payload mass to launch mass does not depend very much on the proportion of the second rocket stage of the launch mass of the total rocket in a wide range.

Yes, it is conceivable that Beck uses a binding resin for its carbon fiber reinforced plastic that is more heat-resistant than normal resins. I would think of phenolic based resins here.

Based on what I saw, Neutron will be fully re-usable.
Unless you are referring to the second stage, which is not really a good comparison, because Starship is the second stage.

Beck indicated that “their” CF will manage heat better. Maybe they have an improved bonding agent? He did imply, without saying it, that there is some proprietary tech here, both in material and manufacture method.

I am curious as to how the tapered shape mitigates heat. I have not been able to find any info on this.

“So it seems Rocket Lab is pushing the tech to build a lighter rocket structure but being more conservative with the engines (less pressure, simpler cycle). SpaceX has done the opposite.”

Starship is fully reusable, Neutron is not. That is, we cannot simply make a comparison. However, here is my Opinion: Musk has at least opted for its fully reusable system concept for the better construction.

We know, at least for Starship’s upper stage, that the steel structure is lighter than a carbon fiber structure. This is because the strength of steel increases at cryogenic temperatures and, above all, the heat shield is for the steel structure is significantly lighter, since the plastic base material of the carbon fiber structure may of course heat up much less than the steel, i.e. it needs to be better protected from the flow of heat .

Given Neutron’s payload capacity without reusing the first stage of around 3% of the launch mass, the first stage does not seem exceptionally light, so I believe the Starship Booster’s dry weight-to-propellant weight ratio is no worse than that of the Neutron rocket’s first stage.
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With the steel construction of Starship’s booster, only minimal heat protection is required in the area of ​​the booster motor section. Beck believes that a clever shaping of his first stage means that its fiber-reinforced plastic does not burn when re-entering the first stage and later during the actual landing. He have to provide this evidence. I see a risk here.

We should also not forget that the price of carbon-fiber-reinforced plastic is orders of magnitude higher than that for steel. Beck also has to buy its carbon fibers on the world market. From an environmental point of view, steel construction is also much more sustainable. Its material is much easier to recycle and dispose of than the fiber-reinforced plastic.

The reason things break off a racecar when they crash is that racecars are built to be as light as possible. The appendages (wings, wheels) are designed to withstand race forces not crash forces. The FIA and other sanctioning bodies now require tethers to keep the heavier wheel assemblies from flying off into spectators. True a metal arm would fail by bending and would be less likely to fracture completely, but it would weigh more than a carbon piece with a tether. The CFRP central structure, the “tub” of a modern racecar, is significantly stronger than the aluminum panel or steel tube structures of old. I have not heard of a case of a tub failing in a crash.

Carbon fiber has been successfully used in aerospace for decades. The Boeing 787 might be regarded as the culmination of that.
A passenger airliner that must have the safety margins to carry passengers over many cycles/years and through various conditions.
So why didn’t SpaceX go carbon?
As I recall Musk saying, cost, and time to manufacture and issues of heat resistance (the carbon fibers can withstand tremendous heat but the resins that hold them together are a different story). Detecting and repairing damage is another issue (though Boeing must have advanced the tech when developing the 787).
So it will be interesting how Rocket Lab addresses these. The fiber laying machines are not new tech – Boeing (their Italian contractor) uses them to make the 787 fuselage and Boing did run into serious production and cost issues on that plane.

So it seems Rocket Lab is pushing the tech to build a lighter rocket structure but being more conservative with the engines (less pressure, simpler cycle). SpaceX has done the opposite.

This is going to be interesting (true SpaceX is much further along, but they still haven’t done a full orbital test yet – unanticipated issues may crop up. And maybe the Raptor production issues are tied to it’s more complex, highly stressed design).

The plan for Neutran may even be for two hinges rather than a single hinge. We will have to wait and hope that we get to see.

The shuttle had a whole side that was a hinge point. And pretty much just one straight seam.

oh you know, I would never have expected the slightest bit of thanks from you.

But, let’s stick to the real facts. Therefore for the files:

I posted my comment with the link to the Neutron rocket video on December 2: 7:29 am (see below). You did put your article with the video on the web on December 2: 10:50 am. So 3 hours and 21 minutes later.

Have a nice day.

https://behindtheblack.com/behind-the-black/points-of-information/musk-shakes-up-raptor-engine-development/#comments

That may be true in more ways than you think. Steel and aluminum are homogenous materials, and they react with the same strength in all directions. Composites, on the other hand, can be laid up in ways to give different reactions for different forces. The sheet in the video may have been made specifically to resist this impact, but the Neutron booster is expected to see compression forces rather than side impact forces, so it is likely to be laid up differently than the example sheet that was shown. As Peter Beck was demonstrating, materials selection is important in engineering, and sometimes composites have advantages that outweigh their disadvantages.

You probably already know that the advantage to the splintering Formula 1 body is to dissipate the kinetic energy of the crashing car so that less energy is available to inflict harm to the driver. It is a safety feature that looks spectacular and hazardous.

Robert Zimmerman.,
I’m not so sure that the visual was bad, but I think he may have underestimated his audience. Or, at least, this audience.

Robert Pratt: Yup, I thought the same thing about that steel, aluminum, carbon fiber demo. Utter fake, and it proved nothing, except showing us Beck doesn’t know much about visuals.

Yeah. I’m kinda jokin’. How many airliners or cargo planes arrive at the terminal with their doors open? In my head, the Neutron with open fairings looks like a baby bird awaiting a worm from its mother.

Sorry for sharing that visual.

Joe noted: “The mass penalty for return to launch site will impact the size of payloads they can launch but still, it is a rather neat idea. To get to the future, we must look to the past kind of thing.”

The mass penalty is the tradeoff for reducing the access price for that mass. There are other tradeoffs, such as beef up the hinges to use the fairings as speed brakes or add real speed brakes designed specifically for the task. Another tradeoff: beefing up the fairing so that it closes nicely or discard them to avoid that problem. The space shuttle payload bay doors closed reliably, so we can be assured that it can be done.

pzatchok noted problems with carbon fiber and concluded: “I am not a fan of CF as a structural body.”

I suspect that this is part of the reason for Rocket Lab’s philosophy of not pushing the limits of the equipment. We already know that carbon composites can be successfully used as an airframe material, as Boeing has been successfully using it for a couple of decades or so.

From what I am reading from the comments here, it seems that Rocket Lab is not relying upon new technologies but is using mature technology and methods in a new combination. I certainly hope (and expect) Neutron is competitive.

The British Black Arrow did this with the payload and third stage. You can see it well on the spare one in the Science Museum in London (https://www.sciencemuseum.org.uk/see-and-do/exploring-space)

While his demo damaged the panel, it is just a demo. I am not seen or heard of that kind of impact testing as part of normal rocket building or testing. Is CF subject to the kind of damage you mention due to just vibration?

Beck has clarified that the 4 part fairings provide the best clearance. No mention of backing/structure.

Side note: The interwebs have dubbed them the “hungry hippo” fairings.

And the carbon fiber body will need all attachment points to be reinforced with metal.

Carbon fiber is not repairable. Just look at all the trouble the VG is having with their carbon fiber parts. You can not just cut it out and put in a new part.
His little demo with did nothing but damage the carbon fiber panel. You can not see it on camera but the gel coat that keeps out the weather is always damaged when the panel bends. Thus letting in water moister. Plus all the fibers get broken on the inside thus making weak areas.

I am not a fan of CF as a structural body.

“What you are witnessing is the democratization of space.”

I also wondered, structurally, how much integrity relies on the closed fairings. It does not seem like much, the whole thing will be lighter and with reduced pressure in the tanks, not as strong. I would think that the closed fairings might improve it.

I also wondered if the shorter, wider body makes it better or worse for launch stresses.
Scott Manley mentioned in a vid how tall and thin rockets, like Falcon 9, introduced structural risk.
This seems to go the opposite way.

The mass penalty for return to launch site will impact the size of payloads they can launch but still, it is a rather neat idea. To get to the future, we must look to the past kind of thing.

I wish them much success on this rocket design.

How long does it take to open a faring? I suspect less time than refueling/maintenance checks. It seems the engineering required to allow an open fairing on landing would not be worth the effort.

This is what I have meant when I have suggested, in other posts, that SpaceX’s compromises have left plenty of room for improvement. Another driver for the differences is that Rocket Lab has other goals with Neutron than SpaceX has with its Starship. I would not be surprised if Rocket Lab also did things differently when they eventually make their own Moon rocket or Mars rocket.

I agree with Col Beausabre’s comment, but I add that there are different goals in these different designs. It isn’t just “what works best,” it also includes what you are doing with what you build. Rocket Lab and SpaceX are being very creative in finding better methods of getting where they want to go.

Changing the way we launch into space was the whole point of the Ansari X-Prize. At that time, reusability was seen as the key, and we now have three companies taking this seriously. Other companies are only reusing the engines, which is admirable, but having to attach those engines to another “fuselage” does not conform to a rapid turnaround paradigm, which was expected from the X-Prize.

sippin_bourbon asked: “If they popped [the fairings] open for drag, that would put a lot of stress on them. But also heat, yes?”

Also heat, yes. They could opened them after they were slow enough, then there would be less heat, little enough that the composite material would not be affected. However, I expect that if they want speed brakes then they would design specific brakes, which would avoid the stress problem on the fairings. Sometimes you can get multiple functions out of an item, but not always. On the third hand, the gripping hand, it may be handy to have the fairings open before landing so that the rocket is ready to load the next payload. I wonder if that is how a 2050 rapid turnaround rocket would work.

It’s enough to drive me Daffy:
https://www.youtube.com/watch?v=L0D9ISBc2ss
(Talk about an “Electron” rocket!)

My comment here was in error. The clamshell fairings open and release the second stage and payload after first stage MECO. My apologies, but I am still skeptical of this as a drag brake. The SpaceX fairings have only to brake themselves / these would also brake the booster and would have to be much more stoutly constructed and supported.

Atlas V 500?